The original owners had used a simple PVC ball valve threaded into a bronze tee coming out of the side of the house (the hose valve came off the end off the tee. Threaded into the other end of the valve was a 3/4" PVC pipe that then went straight down into ground and then branched out to their lawn sprinklers. They then poured the concrete patio slab around the PVC pipe, trapping it in the concrete and making it impossible to unscrew the pipe or the valve if it needed repair.
Which, inevitably, it did. The house slab and patio slab have shifted at different rates, so the pipe no longer points straight down. The PVC ball valve started dripping (very slowly) shortly after I bought the townhouse, and it had by now reached the point where it dripped continuously. Not good, in these days of water shortages and tight finances.
When I had the yard re-landscaped, the landscaper was loath to touch it, expecting the PVC had embrittled over time. He just tapped into the other end of the pipe where it emerged from under the patio slab. The valve itself could not be disassembled and repaired, it had to be replaced.
With the leak as bad as it had become, I had developed a plan: slice through the pipe so the crapped-out valve could be unscrewed, replace it with a proper shutoff valve (with replacable seat and packing), run above-ground-compatible pipe alongside the house, dig down into the irrigation system and patch it in in place of the old supply line. The old pipe could then be sliced off at the concrete.
Step one was to replace the valve. I turned off the water to the house, sliced through the PVC pipe just below the valve, unscrewed it, cleaned off the threads and installed the new brass shutoff valve. Then I could turn the water back on, and proceed at my leisure with Step two: the muddy part of the work, digging, measuring and laying new pipe.
Step one went according to plan. No more drip! Success!
Much to my surprise, I discovered that the pipe emerging from the slab was not brittle at all. Change in plans and a second trip to the hardware store.
Trim the pipe to about 1.5 inches above the slab, and cement a threaded adapter on to it.
Then that threads into a threaded union.. (The union has two flat faces with an o-ring, so you can make all the other connections and then align the to flat faces and compress them together with the outer threaded ring.)
Then a short length of flexible PVC pipe with threaded adapters cemented to each end. Do the last cemented joint after threading all the parts together, and tighten the union together so that it bonds at exactly the correct length.
Voila! Leak is gone, the offset from the drift is handled by the flexible pipe, and with the union in there, it can all be disassembled if it needs to be modified.
|Here's what it looks like after the repair.|
I'll pressure test it in the morning, but everything looks good so far.
Best of all -- no mud.
Color me pleased.